I built something related to this for our webapp. Most of the text in the app is in a language specific "key to text" map that is loaded at runtime. I made a bookmarklet that switched the language into a debug mode where the keys mapped to a "<file>:<language-variants>:<Key>". You could switch to this "mode" with a simple keypress. User then highlighted the key they wanted to change, pressed another key-combo and was presented with the different translations and could change them (and switch back to normal mode for a preview). Lastly they could generate a PR with the changes they wanted and a Dev could make sure the strings worked (e.g. validating they had not removed a needed placeholder etc). All in all pretty nifty tool.
That sounds like a really cool solution! People come up with all kinds of clever workarounds for this problem but then get stuck maintaining and scaling them. This is one of the things that inspired me to join FlyCode solving this once and for all instead of ad-hoc.
